Method for producing moulded parts, in particular for use in the car industry, and a film comprising a coating which is suitable therefor

ABSTRACT

A process for producing moldings, in which a solventborne or aqueous, pigmented coating composition (P) and a free-radically crosslinkable coating composition (K), which after crosslinking to completion produces a transparent coating (KE) are applied to a support sheet, a dried but as yet not completely crosslinked coating (KT) is produced from the coating composition (K), the coated support sheet is shaped and is injection backmolded or foam-backed with a liquid polymeric material, and the coating (KT)—if this has not already taken place—is cured or aftercured; the crosslinkable coating composition (K) comprising a free- radically crosslinkable component (KK) which comprises carbamate and/or biuret and/or allophanate and/or urea and/or amide groups.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Phase Application of Patent ApplicationPCT/EP2005/011142 filed on 17 Oct. 2005, which claims priority toDE102004053245.1, filed 4 Nov. 2004.

FIELD OF THE INVENTION

The present invention relates to a process for producing moldings,especially for use in automobile construction, wherein

-   -   I. a sheet (F) bearing a coating (B) is produced by applying, to        an optionally pretreated surface (T1) of a thermoplastic support        sheet (T)        -   1. a pigmented coating composition (P) and        -   2. a crosslinkable coating composition (K) which comprises a            free-radically crosslinkable component (KK) and which after            crosslinking to completion gives a transparent coating (KE),        -   3. the coating composition (K) applied in stage 2 is dried            and/or partially crosslinked, to give a coating (KT) as yet            not crosslinked to completion,    -   II. the sheet (F) produced in stage I. is inserted into an        opened mold,    -   III. the mold is closed, the side (T2) of the thermoplastic        support sheet (T) not facing the surface (T1) is contacted with        a liquid or softened polymeric material (KM), and the polymeric        material is caused to solidify,    -   IV. the molding obtained in stage III. is removed from the mold,        and    -   V. the coating (KT) is crosslinked to completion at any point in        time in the course of the process,        the crosslinkable coating composition (K) comprising a        free-radically crosslinkable component (KK) which    -   (i) comprises one or more oligo- and/or one or more        poly-urethane (meth)acrylates and    -   (ii) contains on average more than 1, preferably at least 2 and        in particular more than 2 to 10.0 ethylenically unsaturated        double bond(s) per molecule,    -   (iii) has a number-average molecular weight of from 1000 to 10        000 g/mol, preferably from 2000 to 5000 g/mol and more        preferably from 2500 to 3500 g/mol,    -   (iv) has a double bond content of from 1.0 to 5.0 mol of double        bonds per 1000 g of reactive component (KK), preferably a double        bond content of from 1.5 to 4.0 mol of double bonds per 1000 g        of reactive component (KK) and more preferably more than 2.0 to        3.5 mol of double bonds per 1000 g of reactive component (KK),    -   (v) contains on average per molecule >1, preferably >1.4, more        preferably >2 branching points,    -   (vi) contains 5%-50% by weight, preferably 10%-40% by weight,        more preferably 15%-30% by weight, based in each case on the        weight of component (KK), of cyclic structural elements, and    -   (vii) contains at least one aliphatic structural element having        at least 6 carbon atoms in the chain.

The present invention also relates to the use of the moldings thusobtainable and to sheets (F) that are suitable for the process and beara coating.

PRIOR ART

Moldings comprising a polymeric material which has been provided with asheet are known to the skilled worker. Instead of laminating or adheringa sheet to plastic components, an increasing trend nowadays, inindustrial applications as well, is to switch to backing the sheets withthe polymeric material directly in the shaping mold, by injection orcompression molding or foaming (A. Grefenstein, “Folienhinterspritzenstatt Lackieren, Neue Technik für Karosseriebauteile aus Kunststoff”[Injection backmolding of sheets instead of coating: New technology forplastic bodywork components] in Metalloberfläche, 10/99, vol. 53, CarlHanser Verlag, Munich, 1999).

The multilayer color and/or effect sheets used for producing themoldings comprise, as is known, a backing sheet, at least one colorand/or effect basecoat and a clearcoat. They correspond in theirconstruction to the conventional multilayer color and/or effect paintsystems.

Particularly in the field of automobile painting, however, amultiplicity of requirements are imposed on the appearance of themolding's surfaces on the sheet side (cf., e.g., European patent EP 0352 298 B1, page 15 line 42 to page 17 line 40).

The solutions proposed in the prior art, however, do not allow adequatemeeting of these requirements, requirements which are usual in the fieldof automobile painting. Moreover, some of the solutions proposed in theprior art are even contradictory in respect of the glass transitiontemperature that is to be set for the radiation-crosslinkable clearcoatmaterials used.

For instance, WO 00/63015 discloses a process of the aforementioned kindfor producing moldings, in which the crosslinkable coating composition(K) is composed of a radiation-crosslinkable material which comprises abinder having a glass transition temperature of above 40° C. Thetransparent coatings (KE), crosslinked to completion, that are obtainedin this process have unsatisfactory properties, however. In particularthe crosslinking of the transparent coating (KE) is inadequate.

Moreover, the pigmented coating composition used in the processdescribed in WO 00/63015 comprises thermoplastic polymers containingdyes or pigments dispersed in the polymer layer. This color layer isapplied by extrusion, while the use of solventborne or aqueous,pigmented coating compositions and their application techniques are notdescribed.

EP-A-819 516, furthermore, discloses a process for producing moldings,in which a sheet that has been provided with a coating is inserted intoa mold, the mold is closed and contacted with a polymeric material (KM)and the polymeric material (KM) is solidified, the process having thecharacteristic feature that the coating material is only partlycrosslinked before the polymeric material is introduced, and is onlycrosslinked to completion during and/or after the introduction of thepolymeric material (KM). Preference in the process is given to usingradiation-crosslinkable coating compositions having a glass transitiontemperature of below 40° C., based in particular on urethanes. However,further information on the constitution of suitable coating compositionsis absent. EP-B-403 573, moreover, describes a sheet which has beenprovided with a coating and is intended for use in the thermoformingprocess, an essential feature being that a clearcoat material which isuncrosslinked or has a low degree of crosslinking, and has a glasstransition temperature of below 20° C., forms at least part of theclearcoat film.

EP-B-1 144 476, finally, discloses coating compositions which arereferred to as dual-cure compositions, being curable both by thermaladdition and by radiation-induced addition, and discloses their use forproducing thermoformable dry-paint films. The coating compositionsdescribed therein, however, contain free isocyanate groups, which areneeded for the thermal cure. The coating compositions therefore have arelatively complex physical composition. Moreover, operational controlis difficult when the aim is to avoid uncontrolled curing of thethermally reactive constituents during the thermal operating steps, suchas the thermoforming at elevated temperature, for example.

PROBLEM

The problem to be addressed by the present invention was therefore toprovide a process for producing moldings, in which adequate crosslinkingof the coating compositions (K) is ensured, on the one hand. On theother hand, however, the coating (KT) as yet not crosslinked tocompletion must no longer flow and must not be marked by any protectivesheet that may be applied.

Thus, particularly in the case where the moldings are used in theautomobile industry, the moldings ought to satisfy, in terms of theirappearance on the sheet side, the requirements for what is known as aclass A surface.

Additionally the moldings, in terms of their appearance on the sheetside, ought to meet the requirements normally imposed on an automobilefinish (cf. European patent EP 0 352 298 B1, page 15 line 42 to page 17line 40). Thus, in particular, not only the weathering stability butalso the chemical resistance of the transparent coating (KE) crosslinkedto completion must not be inferior to those of conventional automobileclearcoat films. Finally the coating (KE) after crosslinking tocompletion ought to have sufficient scratch resistance.

SOLUTION TO THE PROBLEM

This problem is solved, surprisingly, by means of a process of theaforementioned kind, wherein

-   1. the free-radically crosslinkable component (KK) comprises    carbamate and/or biuret and/or allophanate and/or urea and/or amide    groups and-   2. a solventborne or aqueous coating composition is used as    pigmented coating composition (P).

The present invention also provides for the sheets (F) which bear acoating (B) and are used in the process, and the moldings provided withthe sheet (F), and provides for use thereof.

ADVANTAGES OF THE INVENTION

It is surprising and was not foreseeable that through the use of thespecific component (KK) in the crosslinkable coating compositions (K)coatings are obtained in which, on the one hand, the coating (KT) as yetnot crosslinked to completion no longer flows and is not marked by anyprotective film that may be applied, and, on the other hand,crosslinking of the coating compositions (K) in the course of curing tocompletion is sufficient.

With the process of the invention, therefore, moldings are providedwhich in terms of their appearance on the sheet side ensure class Asurfaces and meet the requirements normally imposed on an automobilefinish (cf. European patent EP 0 352 298 B1, page 15 line 42 to page 17line 40). Thus, in particular, both the weathering stability and thechemical resistance of the completely crosslinked transparent coating(KE) are not inferior to those of conventional automobile clearcoatfilms. The coating (KE) after crosslinking to completion, finally, alsohas sufficient scratch resistance.

DETAILED DESCRIPTION OF THE INVENTION

The Materials used in the Process of the Invention

The Sheet (F) Bearing a Coating (B)

Crosslinkable Coating Composition (K)

It is essential to the invention that the free-radically crosslinkablecomponent (KK) present in the crosslinkable coating component (K)comprises one or more oligourethane (meth)acrylates and/or one or morepolyurethane (meth)acrylates.

Here and in the text below, an oligomer is a compound generallycontaining on average from 2 to 10 base structures or monomer units. Apolymer, in contrast, is a compound generally containing on average morethan 10 base structures or monomer units. Mixtures or physical entitiesof this kind are also referred to by those skilled in the art as bindersor resins.

In contradistinction thereto, here and in the text below, a lowmolecular mass compound is a compound derived essentially only from onebase structure or one monomer unit.

The free-radically crosslinkable component (KK) contains preferably atleast 50%, more preferably at least 70% and very preferably at least 80%by weight, based in each case on the solids content of component (KK),of one or more oligourethane (meth)acrylates and/or one or morepolyurethane (meth)acrylates. In particular the free-radicallycrosslinkable component is composed 100% of one or more oligourethane(meth)acrylates and/or one or more polyurethane (meth)acrylates.

Moreover, the free-radically crosslinkable component (KK) containspreferably not more than 50%, more preferably not more than 30% and verypreferably not more than 20% by weight of further free-radicallycrosslinkable constituents, and in particular contains no suchsubstituents.

The free-radically crosslinkable component (KK) contains preferably lessthan 5%, more preferably less than 1%, by weight, based in each case onthe weight of component (KK), of detectable free isocyanate groups, andin particular contains substantially no such isocyanate groups.

It is also preferred for the free-radically crosslinkable component (KK)present in the crosslinkable coating composition (K) to comprise amixture of different oligo- and/or poly-urethane (meth)acrylates, whichmay also have different double bond contents, molecular weights, doublebond equivalent weights, and may differ in their amount of branchingpoints and their amount of cyclic and relatively long-chain aliphaticstructural elements and amount of carbamate, biuret, allophanate, amideand/or urea groups.

This mixture can be obtained by mixing different oligo- and/orpoly-urethane (meth)acrylates or as a result of the simultaneousformation of different products during the preparation of acorresponding oligo- and/or poly-urethane (meth)acrylate.

Besides the urethane (meth)acrylates, suitable further free-radicallycrosslinkable constituents of component (KK) include monomers, butpreferably oligomers and/or polymers, especially polyester(meth)acrylates, epoxy (meth)acrylates, (meth)acryloyl-functional(meth)acrylic copolymers, polyether (meth)acrylates, unsaturatedpolyesters, amino (meth)acrylates, melamine (meth)acrylates and/orsilicone (meth)acrylates, preferably polyester (meth)acrylates and/orepoxy (meth)acrylates and/or polyether (meth)acrylates. Polymers whichcomprise, in addition to the double bonds, hydroxyl, carboxyl, aminoand/or thiol groups are preferred here.

In order to obtain effective crosslinking it is preferred to usefree-radically crosslinkable components (KK) featuring high reactivityof the functional groups, more preferably free-radically crosslinkablecomponents (KK) which contain acrylic double bonds as functional groups.

The urethane (meth)acrylates can be prepared in a manner known to theskilled worker from isocyanate-functional compound and at least onecompound containing groups that are reactive toward isocyanate groups,by mixing the components in any order, where appropriate at elevatedtemperature.

It is preferred in this case to add the compound containingisocyanate-reactive groups to the isocyanate-functional compound,preferably in two or more steps.

The urethane (meth)acrylates are obtained in particular by initiallyintroducing the di- or polyisocyanate and subsequently adding at leastone hydroxyalkyl (meth)acrylate or hydroxyalkyl ester of otherethylenically unsaturated carboxylic acids, and so first reacting someof the isocyanate groups. Thereafter a chain extender from the group ofthe diols/polyols and/or diamines/polyamines and/or dithiols/polythiolsand/or alkanolamines is added and in that way the remaining isocyanategroups are reacted with the chain extender.

A further possibility is to prepare the urethane (meth)acrylates byreacting a di- or polyisocyanate with a chain extender and then reactingthe remaining free isocyanate groups with at least one ethylenicallyunsaturated hydroxyalkyl ester.

It will be appreciated that all of the hybrid forms of these two methodsare also possible. For example, some of the isocyanate groups of adiisocyanate can be reacted first with a diol, and then a furtherportion of the isocyanate groups can be reacted with the ethylenicallyunsaturated hydroxyalkyl ester, after which the remaining isocyanategroups can be reacted with a diamine.

In general the reaction is conducted at temperatures between 5 and 100°C., preferably between 20 to 90° C. and more preferably between 40 and80° C., and in particular between 60 and 80° C.

It is preferred in this case to operate under water-free conditions.Water-free here means that the water content in the reaction system isnot more 5%, preferably not more than 3% and more preferably not morethan 1% by weight.

In order to suppress polymerization of the polymerizable double bonds itis preferred to operate under an oxygen-containing gas, more preferablyair or air/nitrogen mixtures.

As oxygen-containing gas it is possible with preference to use air or amixture of oxygen or air and a gas which is inert under the conditionsof use. The inert gas used may comprise nitrogen, helium, argon, carbonmonoxide, carbon dioxide, steam, lower hydrocarbons or mixtures thereof.

The oxygen content of the oxygen-containing gas may be for examplebetween 0.1% and 22% by volume, preferably from 0.5% to 20%, morepreferably from 1% to 15%, very preferably from 2% to 10%, and inparticular from 4% to 10% by volume. It will be appreciated that higheroxygen contents can also be used if desired.

The reaction may also be conducted in the presence of an inert solvent,examples being acetone, isobutyl methyl ketone, methyl ethyl ketone,toluene, xylene, butyl acetate or ethoxyethyl acetate.

Via the selection of the nature and amount of di- and/or polyisocyanate,chain extender and hydroxyalkyl esters used, control is exerted over thefurther variables of the urethane (meth)acrylates, such as, for example,double bond content, double bond equivalent weight, amount of branchingpoints, amount of cyclic structural elements, amount of aliphaticstructural elements having at least 6 carbon atoms, biuret, allophanate,carbamate, urea or amide groups and the like.

Through the selection of the particular amounts of di- or polyisocyanateand chain extender used and also through the functionality of the chainextender it is also possible, furthermore, to prepare urethane(meth)acrylates which besides the ethylenically unsaturated double bondsalso contain other functional groups, examples being hydroxyl groups,carboxyl groups, amino groups and/or thiol groups or the like. Theurethane (meth)acrylates preferably also contain hydroxyl groups and/orcarboxyl groups.

Particularly if the urethane (meth)acrylates are to be used in aqueouscoating compositions (K), some of the free isocyanate groups in thereaction mixtures are further reacted with compounds which contain anisocyanate-reactive group, preferably selected from the group consistingof hydroxyl, thiol, and primary and secondary amino groups, especiallyhydroxyl groups, and at least one, especially one, acid group,preferably selected from the group consisting of carboxyl groups,sulfonic acid groups, phosphoric acid groups and phosphonic acid groups,especially carboxyl groups. Examples of suitable compounds of this kindare hydroxyacetic acid, hydroxypropionic acid or gamma-hydroxybutyricacid, especially hydroxyacetic acid.

The polyester (meth)acrylates that are suitable in addition to theurethane (meth)acrylates are known in principle to the skilled worker.They can be prepared by a variety of methods. For example it is possibleto use acrylic and/or methacrylic acid directly as an acid component inthe synthesis of the polyesters. Another possibility is to usehydroxyalkyl esters of (meth)acrylic acid as an alcohol componentdirectly in the synthesis of the polyesters. Preferably, however thepolyester (meth)acrylates are prepared by acrylating polyesters. By wayof example it is possible first to synthesize hydroxyl-containingpolyesters, which are then reacted with acrylic or methacrylic acid. Itis also possible first to synthesize carboxyl-containing polyesters,which are then reacted with a hydroxyalkyl ester of acrylic ormethacrylic acid. Unreacted (meth)acrylic acid can be removed from thereaction mixture by washing, distillation or, preferably, by reactionwith an equivalent amount of a monoepoxide or diepoxide compound, usingappropriate catalysts, such as triphenylphosphine, for example. Forfurther details of the preparation of polyester acrylates reference maybe made in particular to DE-A 33 16 593 and DE-A 38 36 370 and also toEP-A-54 105, DE-B 20 03 579 and EP-B-2866.

The polyether (meth)acrylates that are also suitable are likewise knownas well in principle to the skilled worker. They can be prepared by avariety of methods. By way of example it is possible to obtainhydroxyl-containing polyethers, which are esterified with acrylic acidand/or methacrylic acid, by reacting dihydric and/or polyhydric alcoholswith various amounts of ethylene oxide and/or propylene oxide inaccordance with well-known methods (cf. e.g. Houben-Weyl, volume XIV, 2,Macromolecular Compounds II, (1963)). It is also possible to usepolymerization products of tetrahydrofuran or of butylene oxide.

Via the selection of the nature and amount of alcohol component and acidcomponent used control is exerted over the further variables of thepolyether (meth)acrylates and polyester (meth)acrylates, such as, forexample, double bond content, double bond equivalent weight, amount ofbranching points, amount of cyclic structural elements, amount ofaliphatic structural elements having at least 6 carbon atoms, and thelike.

Epoxy (meth)acrylates are also well known to the skilled worker,moreover, and therefore require no further elucidation. They arenormally prepared by addition reaction of acrylic acid with epoxyresins, such as with epoxy resins based on bisphenol A or with othercommercially customary epoxy resins, for example.

It is further essential to the invention that the free-radicallycrosslinkable component (KK) contains on average more than 1, preferablyat least 2, ethylenically unsaturated double bond(s) per molecule. Withparticular preference the free-radically crosslinkable component (KK)contains more than 2 up to a maximum 10.0, in particular 3.0 to 9.5,preferably 3.5 to 9.0 and very preferably 4.0 to 8.5 double bonds permolecule.

In general the free-radically crosslinkable component (KK) contains notmore than 10% by weight of compounds containing only one curable group,preferably not more than 7.5%, more preferably not more than 5%, verypreferably not more than 2.5%, in particular not more than 1%, andespecially 0% by weight.

Increasing double bond content per molecule of the free-radicallycrosslinkable component (KK) is generally accompanied by an increase inthe crosslinking density of the transparent coating (KE) crosslinked tocompletion.

At the same time, however, increasing double bond content per moleculeof the free-radically crosslinkable component (KK) is generallyaccompanied by a decrease in the breaking elongation of the completelycrosslinked transparent coating (KE); in other words, the system becomesmore brittle. Therefore the completely crosslinked transparent coating(KE) exhibits an increased tendency toward stress cracks after UV curingas the double bond content per molecule increases.

As described above, the double bonds are generally introduced intocomponent (KK) by reacting one or more ethylenically unsaturatedhydroxyalkyl esters with the isocyanate groups of the isocyanate and/orof the isocyanate prepolymer in the case of the urethane (meth)acrylatesand/or with the acid groups of the polyester in the case of thepolyester (meth)acrylates. It is likewise possible, as described above,to react the starting oligomers or starting polymers, such aspolyesters, polyethers, epoxides and acrylate polymers, for example,with acrylic and/or methacrylic acid and/or another ethylenicallyunsaturated acid.

Examples of suitable ethylenically unsaturated hydroxyalkyl esters arehydroxyalkyl esters of acrylic and methacrylic acid, of maleic andfumaric acid, of crotonic and isocrotonic acid and of vinylacetic acid,preferably ethylenically unsaturated hydroxyalkyl esters of acrylicacid. More preferably the ethylenically unsaturated hydroxyethyl and/orhydroxypropyl and/or hydroxybutyl and/or hydroxypentyl and/orhydroxyhexyl esters, very preferably ethylenically unsaturatedhydroxyethyl esters or ethylenically unsaturated hydroxyethyl esterstogether with ethylenically unsaturated hydroxybutyl esters of thestated unsaturated acids are used, particularly those of acrylic acid.

It will be appreciated that for introducing the double bonds intocomponent (KK) it is also possible to use hydroxyalkyl esters havingmore than one double bond per molecule, such as pentaerythrityldiacrylate, triacrylate and tetraacrylate or the like.

With very particular preference the double bonds are introduced intocomponent (KK) using 2-hydroxyethyl acrylate and/or 4-hydroxybutylacrylate and/or pentaerythrityl triacrylate.

The compound used to introduce the double bonds, depending on itsstructure, under certain circumstances itself affects the properties ofthe coating, since not only the double bond content but also, undercertain circumstances, other variables as well, such as the urethanegroup content, for example, are altered. If, for example, the doublebond content of component (KK) is increased by replacing some of thechain extender by hydroxyethyl acrylate, then the urethane group contentwill be altered in accordance with the mass ratio of chain extender tohydroxyethyl acrylate. If, on the other hand, the double bond content ofcomponent (KK) is increased, for example, by using hydroxyalkyl estershaving more than one double bond per molecule instead of hydroxyethylacrylate, such as by using pentaerythrityl triacrylate and/orpentaerythrityl tetraacrylate, for example, then the urethane groupcontent is lowered moderately.

It is further essential to the invention that the free-radicallycrosslinkable component (KK) has a number-average molecular weight offrom 1000 to 10 000 g/mol, preferably from 2000 to 5000 g/mol and morepreferably from 2500 to 3500 g/mol.

The higher the molecular weight of the reactive component (KK), ingeneral the lower the crosslinking density of the completely crosslinkedtransparent coating (KE).

At the same time, in general, the higher the molecular weight of thereactive component (KK), the higher, generally, the resistance of thetransparent coating (KT) which has as yet not crosslinked to completion.

Moreover it is essential to the invention that the free-radicallycrosslinkable component (KK) has a double bond content of from 1.0 to5.0 mol of double bonds per 1000 g of reactive component (KK),preferably a double bond content of from 1.5 to 4.0 mol of double bondsper 1000 g of reactive component (KK) and more preferably a double bondcontent of more than 2.0 to 3.5 mol of double bonds per 1000 g ofreactive component (KK), the values being based in each case on theweight of the free-radically crosslinkable component (KK), but of courseexcluding nonreactive component, such as solvents, water or additives,for example.

As the skilled worker will be aware, the double bond content of thecomponent (KK) is connected not only with the amount of double bonds permolecule but also, in particular, with the number-average molecularweight of component (KK).

As the double bond content of component (KK) drops there is animprovement in the capacity of the transparent coating (KT) which hasbeen dried but as yet not crosslinked to completion to no longer flowand to be no longer marked by any protective film that may be applied.

Decreasing double bond content of component (KK) is accompanied ingeneral by a decrease in the crosslinking density of the transparentcoating (KE) which has been crosslinked to completion.

As the skilled worker is aware, the molecular weight and the double bondcontent can be adjusted by way of the nature and amount of the buildingblock components used and also by way of the reaction conditions.

It is further essential to the invention that the free-radicallycrosslinkable component (KK) contains on average per molecule >1,preferably ≧1.4, more preferably >2, branching points.

A reduction in the average number of branching points per molecule incomponent (KK) is generally accompanied by a decrease in the scratchresistance of the completely crosslinked transparent coating (KE). Atthe same time, with a reduction in the average number of branchingpoints per molecule, there is generally a decrease in the resistance ofthe transparent coating (KT) which has been dried but as yet notcrosslinked to completion.

The average number of branching points per molecule in component (KK) isgenerally adjusted by way of the amount of compounds used forsynthesizing component (KK) that have a functionality of more than 2, inparticular a functionality of at least 3.

The branching points of the free-radically crosslinkable component (KK)are preferably introduced via the use of isocyanates having afunctionality of more than 2, in particular having a functionality of atleast 3.

With particular preference the branching points are introduced by usingtrimeric and/or polymeric isocyanates, especially isocyanurates, and/oradducts or prepolymers having an isocyanate functionality of more than2, especially allophanates and/or biurets, for preparing the oligo-and/or poly-urethane (meth)acrylates employed in the free-radicallycrosslinkable component (KK). With very particular preference thebranching points are introduced via the use of one or more isocyanuratesand/or one or more biurets.

It is, however, also possible, when synthesizing the free-radicallycrosslinkable component (KK), to use alcohols, thiols or amines having afunctionality of more than 2, through the use for example ofpentaerythritol, dipentaerythritol, trimethylolethane,trimethylolpropane, ditrimethylolpropane and trishydroxyethylisocyanurate.

It is further essential to the invention that the free-radicallycrosslinkable component (KK) contains 5%-50%, preferably 10%-40%, morepreferably 15%-30% by weight, based in each case on the weight ofcomponent (KK) (but of course excluding nonreactive components, such assolvents, water or additives, for example) of cyclic structuralelements.

An increasing amount of cyclic structural elements in component (KK)improves the capacity of the transparent coating (KT) which has beendried but as yet not crosslinked to completion to no longer flow and tobe no longer marked by any protective film that may be applied.

As the amount of cyclic structural elements in component (KK) goes upthere is also, inter alia, an increase in the chemical resistance,weathering stability and scratch resistance of the completelycrosslinked transparent coating (KE). Moreover, with an excessivecontent of cyclic structural elements in component (KK), there is adecrease in the breaking elongation of the completely crosslinkedcoating (KE) and hence an increase in brittleness.

It is preferred for the free-radically crosslinkable component (KK) tocomprise, as cyclic structural elements, monocyclic structural elementshaving 4 to 8, more preferably 5 to 6, ring members, and/or polycyclicstructural elements having 7 to 18 ring members, more preferablydicyclic and/or tricyclic structural elements having preferably 10 to12, very preferably tricyclodecane rings, and/or for the cyclicstructural elements to be substituted.

The cyclic structural units may be cycloaliphatic, heterocyclic oraromatic, and are preferably cycloaliphatic and/or heterocyclicstructural units. In particular a combination of cycloaliphatic andheterocyclic structural units is used.

The heterocyclic structural units may be in the chain—as in the casewhere uretdiones are used, for example,—and/or may form the branchingpoints—as in the case where isocyanurates are used, for example. Thecycloaliphatic structural units may likewise be in the chain—as in thecase, for example, where cycloaliphatic diols are used, such ashydrogenated bisphenol A, to synthesize the urethanes, forexample—and/or may form the branching points. With particularpreference, however, the heterocyclic structural units form thebranching points while the cycloaliphatic structural units are in thechain.

Preferred cycloaliphatic structural elements are unsubstituted orsubstituted cyclopentane rings, unsubstituted or substituted cyclohexanerings, unsubstituted or substituted dicycloheptane rings, unsubstitutedor substituted dicyclooctane rings and/or unsubstituted or substituteddicyclodecane rings and/or unsubstituted or substituted tricyclodecanerings, especially unsubstituted or substituted tricyclodecane ringsand/or unsubstituted or substituted cyclohexane rings.

The heterocyclic structural units may be saturated, unsaturated oraromatic. It is preferred to use saturated heterocyclic structuralunits.

The heteroatoms are preferably selected from the group nitrogen and/oroxygen and/or sulfur and/or phosphorus and/or silicon and/or boron, morepreferably nitrogen. The number of heteroatoms per ring is usually 1 to18, preferably 2 to 8 and more preferably 3.

Heterocyclic structural units used with particular preference areisocyanurate rings and/or uretdiones and/or unsubstituted or substitutedtriazine rings, especially isocyanurate rings.

Also suitable in principle for introducing the cyclic structuralelements are aromatic structural elements, in which case the amount ofaromatic structural elements is preferably not more than 10%, morepreferably not more than 5% and very preferably not more than 2% byweight, based in each case on the weight of component (KK). This isbecause aromatic structural elements generally have adverse effects onthe weathering stability of the resultant transparent coating (KE)crosslinked to completion, and so the amount of the aromatic structuralelements is frequently limited for that reason.

The cyclic structural elements are introduced into the reactivecomponent (KK) through the use of corresponding compounds having cyclicstructural elements for preparing component (KK). Component (KK) can beprepared using, in particular, di- and/or polyisocyanates having cyclicstructural elements and/or di- and/or polyols, di- and/or polyamines,and/or di- and/or polythiols having cyclic structural elements.Particular preference is given to using diols and/or polyols and/ordiisocyanates and/or polyisocyanates having cyclic structural elements.

For preparing the oligo- and/or poly-urethane (meth)acrylates used inthe free-radically crosslinkable component (KK) it is thereforepreferred to make at least proportional use, as isocyanate component, ofisocyanurates of di- and/or polyisocyanates, which are commonly employedin the coatings industry. Instead of or together with theseisocyanurates it is possible to use prepolymers and/or adducts,especially biurets and/or allophanates and/or uretdiones, of di- and/orpolyisocyanates, which are commonly used in the coatings industry.Particular preference is given to using isocyanurates and/or biuretsand/or allophanates and/or uretdiones of aliphatic and/or cycloaliphaticisocyanates. In addition it is also possible to use cycloaliphatic di-and/or polyisocyanates alone or in combination with the above-recitedisocyanurates and/or biurets and/or allophanates and/or uretdiones.

Examples of (cyclo)aliphatic di- and/or polyisocyanates which arecommonly used in the coatings industry include hexamethylenediisocyanate, octamethylene diisocyanate, decamethylene diisocyanate,dodecamethylene diisocyanate, tetradecamethylene diisocyanate,trimethylhexane diisocyanate, tetramethylhexane diisocyanate, isophoronediisocyanate, 2-isocyanatopropylcyclohexyl isocyanate,dicyclohexylmethane 2,4′-diisocyanate, dicyclohexylmethane4,4′-diisocyanate, 1,4- or 1,3-bis(isocyanatomethyl)cyclohexane, 1,4- or1,3- or 1,2-diisocyanatocyclohexane, 2,4- or2,6-diisocyanato-1-methylcyclohexane, diisocyanates derived from dimerfatty acids, as sold under the commercial designation DDI 1410 byHenkel, 1,8-diisocyanato-4-isocyanatomethyloctane,1,7-diisocyanato-4-isocyanatomethylheptane or1-isocyanato-2-(3-isocyanatopropyl)cyclohexane, or mixtures of thesepolyisocyanates.

Also suitable, furthermore, are isocyanates containing aromaticstructural elements in which, however, at least some of the isocyanategroups are attached to aliphatic and/or cycloaliphatic radicals,especially 1,3-bis(2-isocyanatoprop-2-yl)benzene (TMXDI).

For preparing the oligo- and/or poly-urethane (meth)acrylates used inthe free-radically crosslinkable component (KK) it is particularlypreferred to make at least proportional use of the isocyanurate of(cyclo)aliphatic isocyanates, especially the isocyanurate of isophoronediisocyanate and/or hexamethylene diisocyanate. Very particularpreference is given to using a mixture of the isocyanurate of isophoronediisocyanate and/or the isocyanurate of hexamethylene diisocyanateand/or the biuret of hexamethylene diisocyanurate and/or1,3-bis(isocyanatomethyl)cyclohexane and/or dicyclohexylmethane4,4′-diisocyanate.

Further of suitability are the higher polyfunctional polyisocyanatesdescribed in EP-B-1 144 476 on page 4 line 43 to page 5 line 31 andbased on isocyanurates (a2.1 therein), uretdiones (a2.2 therein),biurets (a2.3 therein), polyisocyanates containing urethane and/orallophanate groups (a2.4 therein), polyisocyanates containingoxadiazinetrione groups (a2.6 therein), and carbodiimide- oruretonimine-modified polyisocyanates (a.2.7 therein).

For preparing the oligomers and/or polymers used in the free-radicallycrosslinkable component (KK), especially the oligo- and/or poly-urethane(meth)acrylates, preference is also given to making at leastproportional use of cycloaliphatic diols and/or polyols and/orcycloaliphatic diamines and/or polyamines, especially cycloaliphaticdiols, such as cyclohexanedimethanol, 1,2-, 1,3- or 1,4-cyclohexanediol,cyclooctanediol, hydrogenated bisphenol A, hydrogenated bisphenol F andtricyclodecanedimethanol, for example.

Particular preference, for preparing the oligomers and/or polymers usedin the free-radically crosslinkable component (KK), especially theoligo- and/or poly-urethane (meth)acrylates, is given to usinghydrogenated bisphenol A.

As already mentioned, cyclic structural elements can also be introducedby the use of aromatic structural elements—for example, via theproportional use of aromatic isocyanates or trimers and/or prepolymersand/or adducts of aromatic isocyanates, such as of 1,2- 1,3- and1,4-benzene diisocyanate, 2,4- and 2,6-tolylene diisocyanate,4,4′-biphenylene diisocyanate, bis(4-isocyanatophenyl)methane,2,2-bis(4-isocyanatophenyl)propane and the positionally isomericnaphthalene diisocyanates, especially the technical mixtures of 2,4- and2,6-tolylene diisocyanate, for example. Further examples of suitablearomatic structural units are triazine rings.

These structural units may be introduced, for example, via the use oftris(alkoxycarbonylamino)triazines in accordance with U.S. Pat. Nos.4,939,213, 5,084,541 and EP-A-624 577. Derivatives of the aforementionedcompounds can also be employed.

It is essential to the invention, moreover, that the free-radicallycrosslinkable component (KK) comprises at least one aliphatic structuralelement having at least 6 carbon atoms, preferably having 6 to 18 carbonatoms, more preferably having 6 carbon atoms, in the chain.

These structural elements have a flexibilizing effect on component (KK).As the amount of aliphatic structural elements having at least 6 carbonatoms in the chain in component (KK) goes up, therefore, there is adeterioration in the capacity of the transparent coating (KT) which hasbeen dried but is not yet crosslinked to completion to no longer flowand to no longer be marked by any protective film that may be applied.

Moreover, the lower the amount of aliphatic structural elements havingat least 6 carbon atoms in the chain, the better the chemical resistanceof the transparent coating crosslinked to completion.

The free-radically crosslinkable component (KK) contains preferably3%-30%, more preferably 5%-25% and very preferably 8%-20% by weight,based in each case on the weight of component (KK) (but of courseexcluding nonreactive components, such as solvents, water or additives,for example), of aliphatic structural elements having at least 6 carbonatoms in the chain.

Suitability for introduction into component (KK) is possessed by allrelatively long hydrocarbon chains.

The introduction of this aliphatic structural element having at least 6carbon atoms in the chain into the reactive component (KK) takes placethrough the use of corresponding compounds containing this aliphaticstructural element having at least 6 carbon atoms in the chain forpreparing component (KK). For preparing the urethane (meth)acrylates usemay be made in particular of di- and/or polyisocyanates and/or chainextenders (diols and/or polyols, diamines and/or polyamines, dithiolsand/or polythiols, dicarboxylic and/or polycarboxylic acids, etc.)containing this aliphatic structural element having at least 6 carbonatoms in the chain. Particular preference is given to using diols and/orpolyols and/or dicarboxylic and/or polycarboxylic acids and/ordiisocyanates and/or polyisocyanates containing this aliphaticstructural element having at least 6 carbon atoms in the chain.

Suitability is possessed, for example, by dimeric and/or trimeric fattyacids for modifying the di- and/or polyisocyanate.

With particular preference this aliphatic structural element having atleast 6 carbon atoms in the chain is introduced into the free-radicallycrosslinkable component (KK) through the use of correspondinglyfunctionalized derivatives of hexamethylene, in particular through theuse of compounds based on hexamethylene and additionally containing atleast 1, preferably at least 2, isocyanate group(s) or OH and/or NHand/or SH group(s), in the preparation of the oligo- and/orpoly-urethane (meth)acrylates.

Examples of compounds which can be employed include hexamethylenediisocyanate and/or isocyanate-functional trimers and/or polymers and/orisocyanate-functional adducts of hexamethylene diisocyanate, especiallythe biuret and/or the isocyanurate of hexamethylene diisocyanate.Further possibilities for use include hexamethylenediol and/orhexamethylenediamine or similar compounds. A further possibility,finally, is the use of compounds which besides at least 1 ethylenicallyunsaturated double bond and at least 1 reactive group which is reactivetoward isocyanate groups or OH groups or NH groups also contains saidaliphatic structural element having at least 6 carbon atoms in thechain, such as hydroxyhexyl acrylate, for example.

Correspondingly the polyether (meth)acrylates and the polyester(meth)acrylates can also be flexibilized, for example, by reactingcorresponding OH-functional prepolymers and/or oligomers (based onpolyether or polyester) with relatively long-chain aliphaticdicarboxylic acids, especially aliphatic dicarboxylic acids having atleast 6 carbon atoms, such as adipic acid, sebacic acid, dodecanedioicacid and/or dimer fatty acids, for example. This flexibilizing reactioncan be carried out before or after the addition reaction of acrylicand/or methacrylic acid with the oligomers and/or prepolymers.Flexibilization of the epoxy (meth)acrylates is possible in a similarway, for example, by reacting corresponding epoxy-functional prepolymersand/or oligomers with relatively long-chain aliphatic dicarboxylicacids, especially aliphatic dicarboxylic acids having at least 6 carbonatoms, such as adipic acid, sebacic acid, dodecanedioic acid and/ordimer fatty acids, for example. This flexibilization reaction can becarried out before or after the addition reaction of acrylic and/ormethacrylic acid with the oligomers and/or prepolymers.

As set out above, the flexibilization of the polyether (meth)acrylatesand/or of the polyester (meth)acrylates and/or of the epoxy(meth)acrylates, in other words an increase in amount of aliphaticstructural elements having at least 6 carbon atoms in the chain, resultsin a deterioration in the capacity of the transparent coating (KT) whichhas been dried but as yet not crosslinked to completion to no longerflow and to no longer be marked by any protective film that may beapplied.

Moreover, the lower the amount of aliphatic structural elements havingat least 6 carbon atoms in the chain, the better the chemical resistanceof the completely crosslinked transparent coating.

It is essential for the present invention that the free-radicallycrosslinkable component (KK) finally comprises carbamate and/or biuretand/or allophanate and/or urea and/or amide groups. Particularlypreferably the component (KK) comprises biuret and/or allophanategroups.

The higher the amount of carbamate and/or biuret and/or allophanateand/or urea and/or amide groups, the lower is the tendency of theclearcoat film (KT) which has been dried but as yet not crosslinked tocompletion to flow.

The higher the amount of carbamate and/or biuret and/or allophanateand/or urea and/or amide groups, the better too are in general theproperties of the completely crosslinked transparent coating (KE).

With very particular preference the amount of carbamate and/or biuretand/or allophanate and/or urea and/or amide groups is adjusted via thenature and amount of the isocyanate adducts and/or isocyanateprepolymers used.

Preferably the free-radically crosslinkable component (KK) has anaverage carbamate and/or biuret and/or allophanate and/or urea and/oramide groups content of more than 0 to 2.0 mol per 1000 g of reactivecomponent (KK), preferably of from 0.1 to 1.1 mol and particularlypreferably of from 0.2 to 0.7 mol per 1000 g of reative component (KK),the values being based in each case on the weight of the free-radicallycrosslinkable component (KK), but of course excluding non-reactivecomponents such as solvents, water or additives, for example.

The crosslinkable coating composition (K) contains preferably from 30.0%to 99.9%, more preferably from 34.0% to 69.9% and very preferably from38.8% to 59.5% by weight, based in each case on the overall weight ofthe coating composition (K), of component (KK).

The crosslinkable coating compositions (K) preferably comprise at leastone initiator of chemical crosslinking. These initiators are preferablyphotoinitiators. The photoinitiator or photoinitiators is or arepreferably selected from the group consisting of unimolecular (type I)and bimolecular (type II) photoinitiators. More preferably thephotoinitiators of type I are selected from the group consisting ofbenzophenones in combination with tertiary amines, alkylbenzophenones,4,4′-bis(dimethylamino)benzophenone (Michler's ketone), anthrone andhalogenated benzophenones and the photoinitiators of type II areselected from the group consisting of benzoins, benzoin derivatives,especially benzoin ethers, benzil ketals, acylphosphine oxides,especially 2,4,6-trimethylbenzoyldiphenylphosphine oxide and ethyl2,4,6-trimethylbenzoylphenylphosphinate, bisacylphosphine oxides,phenylglyoxylic esters, camphorquinone, alpha-aminoalkylphenones,alpha,alpha-dialkoxyacetophenones and alpha-hydroxyalkylphenones.

If the crosslinking of the coating compositions is completed exclusivelyor additionally by thermal means then they preferably includeC—C-cleaving initiators, preferably benzpinacols. Examples of suitablebenzpinacols are benzpinacol silyl ethers or the substituted andunsubstituted benzpinacols as described in American patent U.S. Pat. No.4,288,527 A in column 3 lines 5 to 44 and WO02/16461, page 8 line 1 topage 9 line 15. Preference is given to using benzpinacol silyl ethers,particularly mixtures of monomeric and oligomeric benzpinacol silylethers.

The amount of the initiators in the crosslinkable coating compositions(K) can vary widely and is guided by the requirements of the case inhand and by the performance properties which it is intended the coatings(KE) produced therefrom should have. The amount is preferably from 0.1%to 10%, in particular from 1.0% to 7.0% by weight, based in each case onthe solids of the coating composition (K).

Furthermore it is possible for the crosslinkable coating compositions(K) to comprise conventional additives in effective amounts. Normallythe amount of these additives is between 0% and 10% by weight,preferably between 0.2% and 5.0% by weight, based in each case on thesolids of the coating composition (K). They are preferably selected fromthe group consisting of light stabilizers, such as UV absorbers andreversible free-radical scavengers (HALS); antioxidants; wetting agents;emulsifiers; slip additives; polymerization inhibitors; adhesionpromoters; leveling agents; film-forming auxiliaries; rheologicalassistants; flame retardants; corrosion inhibitors which are notpigments; free-flow aids; waxes; siccatives; biocides; and flattingagents.

Examples of suitable additives are described in detail in the textbook“Lackadditive” [Additives for coatings] by Johan Bieleman, Wiley-VCH,Weinheim, N.Y., 1998, in D. Stoye and W. Freitag (Editors), in Germanpatent application DE 199 14 896 A 1, column 14 line 26 to column 15line 46, or in German patent application DE 199 08 018 A 1, page 9 line31 to page 8 line 30.

The crosslinkable coating compositions (K) generally further compriseconventional solvents and/or water, but may also be formulatedsubstantially or entirely free from solvent and substantially orentirely free from water, as what are called 100% systems. If thecoating compositions (K) include solvents, they contain preferably from20% to 70%, more preferably from 30% to 64.5% and very preferably from40% to 60% by weight, based in each case on the overall weight of thecoating composition (K), of one or more solvents and/or water,preferably of one or more organic solvents.

Suitable solvents are all those commonly used in clearcoat materials,especially alcohols, glycol ethers, esters, ether esters and ketones,aliphatic and/or aromatic hydrocarbons, such as acetone, methyl isobutylketone, methyl ethyl ketone, butyl acetate, 3-butoxy-2-propanol, ethylethoxypropionate, butylglycol, dipropylene glycol methyl ether, butylglycolate, Shellsol® T, pine oil 90/95, Solventnaphtha®, Shellsol® A,petroleum spirit 135/180 and the like, for example.

The crosslinkable coating composition (K) preferably contains less than20%, in particular less than 10%, more preferably less than 5% byweight, based in each case on the weight of component (KK), and withvery particular preference none at all, of polymeric saturatedconstituent (KS), especially no thermoplastic polymers.

In terms of its method the preparation of the coating compositions (K)has no particular features but instead takes place by the mixing andhomogenizing of the above-described constituents using conventionalmixing techniques and apparatus such as stirred tanks, agitator mills,kneaders, Ultraturrax, inline dissolvers, static mixers, toothed-wheeldispersers, pressure relief nozzles and/or microfluidizers, preferablyin the absence of actinic radiation.

The transparent coating composition is normally applied in an amountsuch as to result in a dry film thickness of at least 30 μm, preferablya dry film thickness of from 30 to 160 μm, more preferably from 40 to 80μm.

Pigmented Coating Composition (P)

As pigmented coating composition (P) use is made of solvent borne oraqueous coating compositions (P) which in general are curable physicallyor thermally and/or with actinic radiation.

The pigmented coating compositions (P) employed normally comprise

-   (I) one or more solvents and/or water,-   (II) one or more binders, preferably one or more polyurethane resins    and/or acrylate resins, more preferably a mixture of at least one    polyurethane resin and at least one acrylate resin,-   (III) optionally at least one crosslinking agent,-   (IV) one or more pigments, and-   (V) optionally one or more customary auxiliaries and additives.

It is preferred to use the customary and known, physically and/orthermally curable, conventional or aqueous basecoat materials (P) suchas are known, for example, from WO 03/016095 A 1, page 10 line 15 topage 14 line 22, or in particular from U.S. Pat. No. 5,030,514, column 2line 63 to column 6 line 68 and column 8 line 53 to column 9 line 10,and also EP-B-754 740, column 3 line 37 to column 6 line 18.

Very particular preference is given to using thermally curable aqueousbasecoat materials (P).

Suitable binders are the polyurethane resins and acrylate resinscommonly used in basecoat materials in the field of the automobileindustry, the flexibility of the binders, in particular, and hence theirsuitability for the process of the invention, being controlled, in amanner known to the skilled worker, via the selection of the nature andamount of the building block components used for preparing thesebinders. For details reference may again be made, for example, to U.S.Pat. No. 5,030,514, column 2 line 63 to column 6 line 68 and column 8line 53 to column 9 line 10.

Additionally the pigmented coating compositions preferably comprise, ascrosslinking agent, at least one additional amino resin. Suitability ispossessed in principle by the amino resins usually used in the field ofthe coatings industry, the properties of the pigmented coatingcompositions being controllable via the reactivity of the amino resins.

The amount of binder and, where appropriate, amino resin in thepigmented coating composition can vary widely and is usually from 0% to70%, preferably from 10% to 60%, by weight of polyurethane resin, from0% to 70%, preferably from 10% to 60%, by weight of acrylate resin, andfrom 0% to 45%, preferably from 5% to 40%, by weight of amino resin,based in each case on the overall amount of binder plus amino resin.

Based on the overall weight of the pigmented coating composition (P) thefraction of binder plus, where appropriate, amino resin is usually from10% to 50% by weight.

The pigmented coating composition (P) further comprises at least onepigment. The pigment is preferably selected from the group consisting oforganic and inorganic, color, effect, color and effect, magneticallyshielding, electrically conductive, anticorrosion, fluorescent andphosphorescent pigments. It is preferred to use the color and/or effectpigments.

Examples of suitable effect pigments, which may also impart color, aremetal flake pigments, such as commercial aluminum bronzes, aluminumbronzes chromated in accordance with DE 36 36 183 A 1, and commercialstainless steel bronzes, and also nonmetallic effect pigments, such aspearlescent pigments and interference pigments, platelet-shaped effectpigments based on iron oxide or liquid-crystalline effect pigments, forexample. For further details refer to Römpp Lexikon Lacke undDruckfarben, Georg Thieme Verlag, 1998, page 176, “Effect pigments” andpages 380 and 381 “metal oxide-mica pigments” to “metal pigments”.

Suitable organic and/or inorganic color pigments are the pigmentsnormally used in the coatings industry.

The amount of the pigments in the coating composition (P) can vary verywidely and is guided primarily by the depth of the color and/or theintensity of the effect which are to be brought about, and also by thedispersibility of the pigments in the coating compositions (P).Preferably the pigment content, based in each case on the coatingcomposition (P), is from 0.5% to 50%, preferably from 1% to 30%, morepreferably from 2% to 20% and in particular from 2.5% to 10% by weight.

Besides the above-described pigments the coating composition (P) maycomprise conventional auxiliaries and additives, such as organic andinorganic, transparent and opaque fillers and nanoparticles, and alsofurther customary auxiliaries and additives, in customary amounts,preferably from 0% to 40% by weight, based on the coating composition(P).

The pigmented coating composition (P) is normally applied in amountssuch as to result in a dry film thickness of at least 30 μm, preferablya dry film thickness of from 30 to 160 μm, more preferably from 50 to150 μm.

Thermoplastic Support Sheet (T)

The thermoplastic support sheet (T) may be in single-layer form or maycomprise at least one further layer.

For instance, on its side (T2) facing away from the subsequent coating(B), (T) may comprise at least one adhesion promoter layer (HS).Preferably, however, the side (T2) of the support sheet is joineddirectly to the polymeric material (KM), without an interlayer.

Located between the surface (T1) and the subsequent coating (B) it isalso possible for there to be at least one, especially one, interlayer(ZS), such as surfacer layer (FS) and/or adhesion promoter layer (HS),for example. Between the surface (T1) and the adhesion promoter layer(HS) and/or between the adhesion promoter layer (HS) and the coating (B)in this case there may be at least one, especially one, transition layer(ÜS). Preferably, however, the coating (B) is disposed directly, i.e.without interlayer, on the surface (T1).

The support sheet (T) is composed essentially or entirely of at leastone thermoplastic polymer. The thermoplastic polymer is preferablyselected from the group consisting of conventional and knownhomopolymers and copolymers of linear, branched, star-shaped, comband/or block construction. The homopolymers and copolymers arepreferably selected from the group consisting of polyurethanes,polyesters, especially polyethylene terephthalates and polybutyleneterephthalates, polyethers, polyolefins, polyamides, polycarbonates,polyvinyl chlorides, polyvinylidene fluorides, poly(meth)acrylates,especially polymethyl methacrylates and polybutyl methacrylates, andimpact-modified polymethyl methacrylates, polystyrenes, especiallyimpact-modified polystyrenes, more particularlyacrylonitrile-butadiene-styrene copolymers (ABS),acrylic-styrene-acrylonitrile copolymers (ASA) andacrylonitrile-ethylene-propylene-diene-styrene copolymers (A-EPDM);polyetherimides, polyetherketones, polyphenylene sulfides, polyphenyleneethers, and blends of these polymers.

By ASA are meant, in general, impact-modified styrene/acrylonitrilepolymers, in which graft copolymers of vinylaromatic compounds,especially styrene, and of vinyl cyanides, especially acrylonitrile, onpolyalkyl acrylate rubbers are present in a copolymer matrix comprising,in particular, styrene and acrylonitrile.

With particular advantage use is made of ASA, polycarbonates, blends ofASA and polycarbonates, polypropylene, polymethyl methacrylates orimpact-modified polymethyl methacrylates, especially blends of ASA andpolycarbonates, preferably with a polycarbonate fraction >40%, inparticular >50%.

Materials used with preference for the support sheet (T) are also, inparticular, the thermoplastic polymers described in DE-A-101 13 273 onpage 2 line 61 to page 3 line 26.

The homopolymers and copolymers may comprise the additives conventionalwithin the field of thermoplastics. They may further compriseconventional fillers, including reinforcing fillers, and fibers. Notleast they may also comprise the pigments, including effect pigments,and/or conventional dyes, and so allow the shade of the support sheetsto be matched to the shade of the coating obtained from the pigmentedcoating compositions (P).

The layer thickness of the support sheet (T) is usually more than 0.5mm, preferably between 0.7 and 2.0 mm and more preferably between 0.9and 1.2 mm.

As transition layers (ÜS) it is possible to use conventional layers,with a thickness of preferably from 1 to 50 μm, of thermoplasticmaterials, in particular of the thermoplastic polymers described above.

The adhesion promoter layer is used when adhesion between the supportsheet (T) and the polymeric material (KM) is inadequate: for example, ifpolyolefins are employed for (T) or (KM). As adhesion promoter layer(HS) it is possible to use layers of customary adhesion promoters with athickness of from 1 to 100 μm preferably, these layers beingconventional and as described, for example, in DE-A-101 13 273 on page 4lines 27 to 29.

Polymeric Material (KM)

The liquid or softened polymeric material (KM) preferably comprises atleast one melted or softened, thermoplastic polymer, in particular atleast one of the thermoplastic polymers described above in connectionwith the support sheet (T), or consists thereof.

It is preferred to use polymeric materials which comprise fibers, theterms “fibers” also including platelet-shaped products. Examples ofsuitable fibers are carbon, aramid, steel or glass fibers and aluminumflakes, preferably glass fibers.

Also suitable, for example, are the polymeric materials described inDE-A-101 13 273 on page 4 line 44 to page 5 line 45.

The version of the process in which a melted or softened thermoplasticpolymer of this kind is used is also referred to as backing by injectionmolding or by compression molding.

Alternatively the liquid or softened polymeric material may comprise aconventional reactive mixture which forms the solid polymeric material(KM) in the shaping or backing mold. In this case the polymeric material(KM) may likewise comprise the additives described above in connectionwith the support sheet (T). It is also possible, furthermore, to usepolymeric materials (KM) which include pore-forming blowing agents.Examples of suitable reactive mixtures are the known reactive mixturesthat are normally used in foam backing processes, especiallypolyurethane foams, examples being the reactive mixtures described inEP-B-995 667, especially in EP-B-995 667, column 2 line 40 to column 3line 14; column 5 lines 23 to 29; and column 8 lines 33 to 38.

The version of the process in which a reactive mixture of this kind ormixture (KM) including blowing agent is used is also referred to as foambacking by reaction-injection molding, RIM.

Protective Film (S)

Suitable protective films (S) are all commonly used protective films,which may be in single-layer or multilayer form. Use is made inparticular of the protective films described in DE-A-10335620, page 17line 20 to page 19 line 22.

Particularly suitable protective films (S) are those based onhomopolymers and copolymers of polyethylene, polypropylene, ethylenecopolymers, propylene copolymers, and ethylene-propylene copolymers.

The protective film is preferably selected such that with a layerthickness of 50 μm it has a transmittance >70% for UV radiation andvisible light with a wavelength of from 230 to 600 nm.

Additionally it is preferred to use protective films which in thetemperature range from room temperature to 100° C. have a storagemodulus E′ of at least 10⁷ Pa and also have a breaking elongation >300%at 23° C. both longitudinally and transversely to the preferentialdirection generated during the production of the protective film bymeans of directed production methods. With particular preference theside of the protective film that faces the coating (B) additionally hasa hardness <0.06 GPa at 23° C. and a roughness as determined by atomicforce microscopy (AFM) corresponding to an R_(a) value from 50 μm²<30nm.

With very particular preference the protective films (S) are from 10 to100 μm, in particular from 30 to 70 μm, thick.

The protective films (S) for use in accordance with the invention areconventional and are sold, for example, by Bischof+Klein, D-49525Lengerich, under the designations GH-X 527, GH-X 529 and GH-X-535.

Process for Producing Moldings

Process Step I

The pigmented coating composition (P) can be applied in one layer or intwo or more layers to the thermoplastic support sheet.

If the pigmented coating composition (P) is applied in only one layerthen this is done preferably by means of a nondirected applicationmethod, which does not bring about an arrangement of the pigments in apreferential direction in the resultant pigmented coatings. In otherwords, the pigments are distributed isotropically in the coating.Examples of suitable nondirected application methods and apparatustherefor are known from WO 03/016095 A 1, page 20 line 4 to page 23 line25. Pneumatic or electrostatic spraying apparatus is used in particular,as described in WO 03/016095 A 1, page 20 line 4 to page 23 line 25.

If the pigmented coating composition (P) is applied in two or morelayers then this is preferably done such that the first layer or, wherethere are more than 2 pigmented layers in total, the first layers is orare applied by means of a directed application method which brings aboutan arrangement of the pigments in a preferential direction, i.e. ananisotropic distribution of the pigments, in the resultant pigmentedcoating. Examples of suitable directed application methods are knownfrom WO 03/016095 A 1, page 15 lines 6 to 19. Knife coaters, castingapparatus and rollers are used in particular. The last pigmented layeris then applied by means of the above-described nondirected applicationmethod.

The coating composition (K) may likewise be applied in one or morelayers, preferably in one layer, by means of the above-describeddirected and nondirected application methods. Preferably the coatingcomposition (K) is applied by directed application methods, verypreferably using cast-film extruders. The coating compositions (K) arepreferably applied and processed further in the absence of actinicradiation.

In general, moreover, in the case of multilayer application of thepigmented coating compositions (P), the most recent layer of coating isflashed off briefly, preferably at an elevated temperature, before thenext layer of the pigmented coating composition is applied. Similarly,prior to the application of the coating composition (K), the pigmentedcoating composition (P) applied beforehand is flashed off briefly,preferably at an elevated temperature. This flashing off is commonlyalso referred to as conditioning.

It is essential, however, that, following its application and beforeprocess step II, the applied coating composition (K) is dried and/orpartially crosslinked to give a coating (KT) as yet not crosslinked tocompletion.

The coating (KT) thus obtained must no longer flow or be marked by anyprotective film that may be applied. This ensures that moldings areobtained which in terms of their sheet-side appearance satisfy therequirements imposed on a class A surface.

For the drying or conditioning of the wet pigmented coatings and alsothe wet transparent coatings it is preferred to use thermal and/orconvection methods, in which case conventional apparatus is employed,such as tunnel ovens, NIR and IR radiant heaters, fans and blowingtunnels. Combinations of such apparatus may also be used.

Normally the drying or conditioning of the transparent coating takesplace such that the coating is flashed off at ambient temperature(generally 25° C.) for a time of from 2 to 30 minutes and then dried atelevated temperature (preferred oven temperature from 80 to 140° C.) fora time of from 5 to 30 minutes.

For a process employed with preference for applying and drying thepigmented coating compositions (P) and the coating compositions (K)reference may also be made to the as yet unpublished German patentapplication bearing the file reference 10 2004 010 787.4, page 16 line 4to page 25 line 8.

With particular preference, therefore, the application and conditioningof the pigmented coating composition (P) and of the crosslinkablecoating composition (K) take place such that

-   a. the pigmented coating composition (P) is applied to the support    sheet to give a wet pigmented layer 1 a, which is adjusted to a    residual volatiles content of x<10% by weight, based on the    pigmented layer, to give a conditioned pigmented layer 1 b,-   b. the assembly made up of support sheet and conditioned layer 1 b    is adjusted to a temperature of <50° C., preferably <35° C., at the    surface of the layer 1 b,-   c. if desired, a second pigmented coating composition (P) or the    same pigmented coating composition (P) for a second time is applied    to the conditioned and heat-treated layer 1 b to give a wet    pigmented layer 2 a, which is adjusted to a residual volatiles    content of y<10% by weight, based on the pigmented layer, to give a    conditioned layer 2 b,-   d. if desired, the assembly made up of support sheet and conditioned    layers 1 b and 2 b is adjusted to a temperature of <50° C.,    preferably <35° C., at the surface of the layer 2 b,-   e. the crosslinkable coating composition (K) is applied to the    conditioned and heat-treated layer 1 b or 2 b to give a wet layer 3    a which is adjusted to a residual volatiles content of z<5% by    weight, based on the layer of the coating composition (K), to give a    conditioned, deformable layer 3 b curable thermally and/or with    actinic radiation.

This process is performed with particular preference such that

in process step a

-   in the first drying section an average drying rate of from 10% to    40% by weight/min is employed, based on the overall amount of    volatiles in the applied pigmented layer, until a residual volatiles    content of x=12% to 30% by weight is achieved, based on the    pigmented layer, and in the last drying section an average drying    rate of from 1% to 6% by weight/min is employed, based on the    overall amount of volatiles in the applied pigmented layer, until a    residual volatiles content of x<10% by weight, more preferably <7%    by weight, in particular <5% by weight is achieved, based in each    case on the pigmented layer,    and/or in process step c-   in the first drying section an average drying rate of from 10% to    40% by weight/min is employed, based on the overall amount of    volatiles in the applied layer, until a residual volatiles content    of y=12% to 30% by weight is achieved, based on the pigmented layer,    and-   in the last drying section an average drying rate of from 1.5% to 4%    by weight/min is employed, based on the overall amount of volatiles    in the applied pigmented layer, until a residual volatiles content    of y<10% by weight, more preferably <7% by weight, in particular <5%    by weight is achieved, based in each case on the pigmented layer,    and/or in process step e-   in the first drying section an average drying rate of from 10% to    30% by weight/min is employed, based on the overall amount of    volatiles in the applied layer of coating composition (K), until a    residual volatiles content of z=10% to 15% by weight is achieved,    based on the layer of coating composition (K), and-   in the last drying section an average drying rate of from 0.5% to 3%    by weight/min is employed, based on the overall amount of volatiles    in the applied layer of coating composition (K), until a residual    volatiles content of z<7% by weight, more preferably <5% by weight,    in particular <3% by weight is achieved, based in each case on the    layer of coating composition (K).

With process step e, preferably, the coating (KT) as yet not crosslinkedto completion is obtained.

The assemblies made up of support sheet and pigmented layer that resultin the course of the process of the invention can be wound, stored,transported and supplied to another application apparatus before thenext layer in each case is applied, and can be coated with said nextlayer in said other application apparatus. For this purpose theassemblies may be lined with protective film, which is removed againbefore the next layer is applied.

Preferably, however, the process of the invention is carried out in acontinuous installation which includes all of the necessary applicationapparatus and apparatus for conditioning. Additionally this continuousinstallation includes conventional apparatus for supplying the pigmentedand transparent coating compositions to the application apparatus;unwinders for the support sheets and protective films, and winders forthe multilayer sheets F; drives for conveying the sheets and, whereappropriate, the application apparatus; suction apparatus for thevolatiles; cooling fans and/or chill rolls for adjusting the surfacetemperature of the conditioned coating layers; measurement and controlapparatus; and, where appropriate, apparatus for shielding from actinicradiation.

Process Steps II to IV

Before the process step II the above-described sheet (F) produced instage I is preferably inserted into an opened mold, in particular athermoforming mold. For this purpose the sheet (F) can be wound from aroll and cut into suitably sized sections. Thereafter the sheet (F) orthe cut-to-size sections can be subjected to preliminary shaping,particularly in the thermoforming mold, and in particular can be adaptedto the contours of the backing molds. These three-dimensionallypreshaped sections are then inserted in process step II into a mold, inparticular into a backing mold.

An alternative possibility is to insert the sheet (F) or cut-to-sizesections of the sheet (F) directly, i.e., without three-dimensionalshaping beforehand, in process step II into a mold, in particular abacking mold or shaping mold, and to carry out shaping directly in thismold.

In process step III the mold is closed and the side (T2) of thethermoplastic support sheet (T) that faces away from the surface (T1) iscontacted with a liquid or softened polymeric material (KM), as a resultof which the coated thermoplastic support sheet (T) is, whereappropriate, shaped and firmly joined to the polymeric material (KM).Subsequently the polymeric material (KM) is solidified.

In process step IV the molding obtained in stage III is removed from themold. It can be processed further immediately thereafter or stored untilprocess step V is carried out.

Process steps II to IV are known to the skilled worker and alsodescribed in a multitude of references. Reference may be made here onlyto DE-A-101 13 273, page 5 line 47 to page 7 line 35.

Process Step V

In process step V the coating (KT) is crosslinked to completion. Thistakes place at any desired point in time in the course of the process.Crosslinking may also take place in two or more steps, so that—followingone or more partial cures, where appropriate—complete crosslinking takesplace. Where appropriate it is also possible in this process step forthe pigmented coating (P) to be crosslinked or additionally crosslinked.

As already described in connection with the drying of the transparentcoating (KT) it is essential to the invention that the coating (KT) isas yet not crosslinked to completion, but at the same time that (KT) hasa resistance such that it no longer flows and such that it is not markedby any protective film that may be applied.

This coating (KT) as yet not crosslinked to completion can becrosslinked completely in process step (I) and/or after process step (I)and/or in process step (III) and/or after process step (IV).

The transparent coating (KT) as yet not crosslinked to completion,however, has better thermoformability than the completely crosslinkedcoating (KE). Preferably, therefore, the coating (KT) is crosslinked tocompletion following deformation, in particular after the sheet (F) hasbeen adapted to the contour of the mold into which the sheet (F) isinserted in process step (II). Since, however, the mechanicalload-bearing capacity of the transparent coating (KT) as yet notcrosslinked to completion is reduced as compared with that of thecompletely crosslinked coating (KE), and since as high as possible aload-bearing capacity is desirable when injection backmolding, simplybecause of the high pressures that are normally employed, it is alsopreferred, in order to prevent damage to the sheet (F) and hence toensure the required class A surface, to effect crosslinking tocompletion prior to injection backmolding, in other words before processstep (III), and in particular before process step (II) as well, butafter the thermoforming.

A further possibility is to carry out process step V at an elevatedtemperature, preferably at a temperature between 25 and 150° C., inparticular between 40 and 120° C. and very preferably between 50 and100° C. The elevated temperature may be attained by means of specificheating, by means for example of IR lamps, heated air or other customaryapparatus. An alternative possibility, however, is to carry out processstep V immediately following process step IV and so to utilize thetemperature increase brought about by the injection backmoldingoperation.

The crosslinking of the coating composition (K) to completion takesplace preferably by means of high-energy radiation, in particular bymeans of UV radiation. With particular preference the crosslinking tocompletion is carried out as described in WO 03/016095 A 1, page 27 line19 to page 28 line 24. An alternative possibility is to carry out thecrosslinking to completion thermally, exclusively or in addition toradiation curing. In that case the thermal crosslinking to completiontakes place preferably during and/or immediately after process step IV,so as to utilize the temperature increase brought about by the injectionbackmolding operation.

Crosslinking to completion is preferably carried out using radiationwith a radiation dose of from 100 to 6000, preferably from 200 to 3000,more preferably from 300 to 2500 and very preferably from 500 to 2000mJcm⁻², the range <2000 mJcm⁻² being especially preferred.

Irradiation can be carried out under an oxygen-depleted atmosphere.“Oxygen-depleted” means that the oxygen content of the atmosphere islower than that of air (20.95% by volume). In principle the atmospheremay also be oxygen-free: in other words, may constitute an inert gas.Owing to the lack of the inhibitory effect of oxygen, however, this mayproduce a sharp acceleration in radiation curing, possibly leading toinhomogeneities and stresses in the crosslinked materials of theinvention. It is therefore of advantage not to lower the oxygen contentof the atmosphere to zero % by volume.

Use of the Moldings

The moldings obtained by the process of the invention have an extremelybroad spectrum of possible applications. For instance they can be usedto outstanding effect as interior or exterior bodywork components, ascomponents for shipbuilding and aircraft construction, as components forrail vehicles or as components for household and electrical appliances,for buildings, windows, doors, furniture and articles of everyday use ofany kind. They are preferably used as interior or exterior bodyworkcomponents or modules, in particular for automobiles, trucks and buses.

Since the moldings, in their sheet-side appearance, satisfy therequirements of a class A surface and meet the requirements normallyimposed on an automotive finish, they are suitable to particularlyoutstanding effect as exterior mounted components for automobile bodies,especially for bodies of top-class automobiles, such as, for example,for producing hardtops, tailgates, bonnets, fenders, bumpers, and thelike, for example.

EXAMPLE 1

The Preparation of the Organic Solution of a Urethane Acrylate (OrganicSolution of Component (KK1))

A urethane acrylate was prepared from the building block components setout below by coarsely dispersing the hydrogenated bisphenol A in2-hydroxyethyl acrylate at 60° C. with stirring. Added to thissuspension were the isocyanates, hydroquinone monomethyl ether,1,6-di-tert-butyl-para-cresol and methyl ethyl ketone. After dibutyltindilaurate had been added the mixture heated up. Stirring was carried outat an internal temperature of 75° C. for a number of hours until therewas virtually no longer any change in the NCO value of the reactionmixture. The free isocyanate groups still present where appropriateafter the reaction were reacted by adding a small amount of methanol.

104.214 g of hydrogenated bisphenol A (corresponding to 0.87 equivalentof hydroxyl groups),

147.422 g (corresponding to 0.77 equivalent of isocyanate groups) ofBasonat® HI 100 from BASF AG=commercial isocyanurate of hexamethylenediisocyanate with an NCO content of 21.5%-22.5% (DIN EN ISO 11909),

147.422 g (corresponding to 0.77 equivalent of isocyanate groups) ofBasonat® HB 100 from BASF AG=commercial biuret of hexamethylenediisocyanate with an NCO content of 22%-23% (DIN EN ISO 11909),

124.994 g (corresponding to 0.51 equivalent of isocyanate groups)Vestanat® T1890 from Degussa=commercial isocyanurate of isophoronediisocyanate with an NCO content of 11.7%-12.3% (DIN EN ISO 11909)

131.378 g of 2-hydroxyethyl acrylate (corresponding to 1.13 equivalentsof hydroxyl groups)

0.328 g of hydroquinone monomethyl ether (0.05% on solids)

0.655 g of 1,6-di-tert-butyl-para-cresol (0.1% on solids)

methyl ethyl ketone (70% solids)

0.066 g of dibutyltin dilaurate (0.01% on solids)

4.500 g of methanol (corresponding to 0.14 equivalent of hydroxylgroups)

The component (KK1) thus obtained has the following characteristics:

-   -   on average 4.6 ethylenically unsaturated double bonds per        molecule    -   a double bond content of 1.74 mol of double bonds per 1000 g of        urethane acrylate solids    -   on average 2.2 branching points per molecule    -   25% by weight of cyclic structural elements, based on the solids        content of the urethane acrylate.        The Preparation of a UV-Curable Coating Composition (K1)

143.00 parts by weight of the above-described organic solution ofurethane acrylate were charged to a suitable stirred vessel.

Added to the initial charge over the course of 30 minutes was a mixtureof 1.0 part by weight of Tinuvin® 292 (commercial HALS light stabilizerfrom Ciba Specialty Chemicals, based on a mixture ofbis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate), 2.4 parts by weight ofthe commercial light stabilizer solution Tinuvin® 400 (commercial lightstabilizer from Ciba Specialty Chemicals, based on a mixture of2-(4-((2-hydroxy-3-dodecyloxypropyl)oxy)-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazineand 2-(4-((2-hydroxy-3-tridecyloxypropyl)oxy)-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine 85%strength in 1-methoxy-2-propanol), 0.8 part by weight of Lucirin® TPO-L(commercial photoinitiator from BASF Aktiengesellschaft, based on ethyl2,4,6-trimethylbenzoylphenylphosphinate), 2.40 parts by weight ofIrgacure® 184 (commercial photoinitiator from Ciba Specialty Chemicals,based on 1-hydroxycyclohexyl phenyl ketone) used in the form of 3.0parts of an 80% strength solution in acetone, and 0.2 part by weight ofa commercial polyether-modified polydimethylsiloxane (used in the formof 1.7 parts of a commercial 12.5% strength solution of thepolyether-modified polydimethylsiloxane in xylene/monophenylglycol7/2Byk® 306 from Byk Chemie) with continuous stirring at roomtemperature and the solution was adjusted with 3-butoxy-2-propanol to asolids content of 48%. The resulting mixture was subsequently stirred atroom temperature for 30 minutes.

The Production of a Coated Thermoplastic Support Sheet 1

The support sheet used was a thermoplastic film of Luran® S 778 TE fromBASF Aktiengesellschaft, with a thickness of 800 μm. The surface of thesupport sheet to be coated was subjected to corona pretreatment at 0.5kilowatt.

The film was coated on one side with a metallic aqueous basecoatmaterial (shade: “Silver Metallic”). Using a box-type coating bar with awidth of 37 cm, the basecoat material was applied to the support sheetwith a belt speed of 0.5 m/min. Application was carried out with agentle air flow of 0.2 m/s, a constant temperature of 21±1° C. and aconstant relative humidity of 65±5%. The thickness of the resulting wetbasecoat layer 1 a was 100 μm. The wet basecoat layer 1 a was flashedoff under these conditions for 3 minutes and then dried, as described onpage 28 lines 4 to 23 of the as yet unpublished German patentapplication bearing the file reference 10 2004 010 787.4, to a residualvolatiles content of x=4% by weight, based on the basecoat layer. Theresulting conditioned basecoat layer 1 b, with a thickness of about 20μm, was adjusted using chill rolls to a surface temperature <30° C.

The same basecoat material was applied to the conditioned andheat-treated basecoat layer 1 b under the following conditions, using asystem for pneumatic spray application:

-   -   outflow rate: 100 ml/min;    -   air pressures: atomizer air: 2.5 bar; horn air: 2.5 bar;    -   speed of movement of the nozzles: high enough to result in 60%        overlapping of the spray jets;    -   nozzle-film distance: 30 cm.

Application was carried out with a gentle air flow of 0.5 m/s (verticalflow impingement on the film), a constant temperature of 21±1° C. and aconstant relative humidity of 65±5%. The thickness of the resulting wetbasecoat layer 2 a was 50±2 μm. The basecoat layer 2 a was flashed offunder these conditions for 3 minutes and then dried, as described onpage 29 lines 12 to 30 of the as yet unpublished German patentapplication bearing the file reference 10 2004 010 787.4, to a residualvolatiles content of y=4% by weight, based on the basecoat layer. Theair temperature here was 90° C., the atmospheric humidity 10 g/min, andthe air speeds 10 m/s. The resulting conditioned basecoat layer 2 b,with a thickness of about 10 μm, was adjusted using chill rolls to asurface temperature <30° C.

Using a box-type coating bar with a width of 37 cm, the above-describedcoating composition (K) was applied to the conditioned and heat-treatedbasecoat layer 2 b. Application was carried out with a gentle air flowof 0.2 m/s, a constant temperature of 21±1° C. and a constant relativehumidity of 65±5%. The thickness of the resulting wet clearcoat layer 3a was 120 μm. It was flashed off under the stated conditions for 6minutes and then dried, as described on page 30 lines 10 to 29 of the asyet unpublished German patent application bearing the file reference 102004 010 787.4, to a residual volatiles content of z=2.5% by weight,based on the clearcoat layer. The air temperature in the oven was 119°C. for all drying stages. The resulting coating (KT), dried but as yetnot crosslinked to completion, and with a thickness of 60 μm, wasadjusted using chill rolls to a surface temperature <30° C. and coatedwith the polypropylene protective film described in DE-A-10335620,Example 1 (commercial product GH-X 527 from Bischof+Klein, Lengerich,Germany).

The resultant multilayer sheet (F) was wound to a roll and stored inthat form prior to its further use.

The Production of Polymer Moldings

The multilayer sheet (F) was preformed. Subsequently the transparentcoating as yet not crosslinked to completion was partially crosslinkedwith UV radiation through the protective film. The positive tool usedwas a cube. The resulting preformed part was inserted into a mold. Themold was closed and the cube was injection backmolded with a liquidpolymeric material. The resultant polymer molding was cooled and removedfrom the mold. Subsequently the partially crosslinked transparentcoating was crosslinked to completion with UV radiation. Thereafter theprotective film was removed.

The polymer moldings produced in this way had a high-gloss surface whichwas free from defects.

EXAMPLE 2

The Preparation of the Organic Solution of a Urethane Acrylate (OrganicSolution of Component (KK2))

A urethane acrylate was prepared from the building block components setout below by coarsely dispersing the hydrogenated bisphenol A in4-hydroxybutyl acrylate and pentaerythritol tri/tetraacrylate at 60° C.with stirring. Added to this suspension were the isocyanates,hydroquinone monomethyl ether, 1,6-di-tert-butyl-para-cresol and butylacetate. After dibutyltin dilaurate had been added the mixture heatedup. Stirring was carried out at an internal temperature of 75° C. for anumber of hours until there was virtually no longer any change in theNCO value of the reaction mixture. The free isocyanate groups stillpresent where appropriate after the reaction were reacted by adding asmall amount of methanol.

227.7 g of hydrogenated bisphenol A (corresponding to 1.89 equivalentsof hydroxyl groups),

178.2 g of 4-hydroxybutyl acrylate (corresponding to 1.24 equivalents ofhydroxyl groups)

701.3 g of pentaerythritol tri/tetraacrylate (OH number=110 mg(KOH)/g,corresponding to 1.37 equivalents of hydroxyl groups)

325.69 g (corresponding to 1.71 equivalents of isocyanate groups) ofBasonat® HI 100 from BASF AG=commercial isocyanurate of hexamethylenediisocyanate with an NCO content of 21.5%-22.5% (DIN EN ISO 11909),

325.69 g (corresponding to 1.74 equivalents of isocyanate groups) ofBasonat® HB 100 from BASF AG=commercial biuret of hexamethylenediisocyanate with an NCO content of 22%-23% (DIN EN ISO 11909),

147.38 g (corresponding to 1.13 equivalents of isocyanate groups) ofDesmodur® W from Bayer MaterialScience AG=commercial dicyclohexylmethanediisocyanate with an NCO content of ≧31.8%

0.953 g of hydroquinone monomethyl ether (0.05% on solids)

1.906 g of 1,6-di-tert-butyl-para-cresol (0.1% on solids)

816.84 g of butyl acetate (corresponding to 70% solids)

0.7624 g of dibutyltin dilaurate (0.04% on solids)

17.1 g of methanol (corresponding to 0.53 equivalent of hydroxyl groups)

The component (KK2) thus obtained has the following characteristics:

-   -   on average 7.1 ethylenically unsaturated double bonds per        molecule    -   a double bond content of 2.92 mol of double bonds per 1000 g of        urethane acrylate solids    -   on average 1.5 branching points per molecule    -   16% by weight of cyclic structural elements, based on the solids        content of the urethane acrylate        The Preparation of a UV-Curable Coating Composition (K2)

143.00 parts by weight of the above-described organic solution ofurethane acrylate (KK2) were charged to a suitable stirred vessel. Addedto the initial charge over the course of 30 minutes was a mixture of 1.0part by weight of Tinuvin® 292 (commercial HALS light stabilizer fromCiba Specialty Chemicals, based on a mixture ofbis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate), 2.35 parts by weight ofTinuvin® 400 (commercial light stabilizer from Ciba Specialty Chemicals,based on a mixture of2-(4-((2-hydroxy-3-dodecyloxypropyl)oxy)-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazineand2-(4-((2-hydroxy-3-tridecyloxypropyl)oxy)-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,0.8 part by weight of Lucirin® TPO-L (commercial photoinitiator fromBASF Aktiengesellschaft, based on ethyl2,4,6-trimethylbenzoylphenylphosphinate), 2.40 parts by weight ofIrgacure® 184 (commercial photoinitiator from Ciba Specialty Chemicals,based on 1-hydroxycyclohexyl phenyl ketone) and 0.40 part by weight ofByk® 325 (commercial additive from Byk Chemie based on apolyether-modified polymethylalkylsiloxane) with continuous stirring atroom temperature and the solution was adjusted with 1-methoxy-2-propylacetate to a solids content of 51%. The resulting mixture wassubsequently stirred at room temperature for 30 minutes.

2.2. Production of the Thermoformable Sheet 2 Provided with a Coating

The UV-curable coating material (K2) was used in the same way as inexample 1 to produce a sheet bearing a coating.

1. A process for producing moldings, the process comprising I. applyinga pigmented coating composition (P) and a crosslinkable coatingcomposition (K) to an optionally pretreated surface (T1) of athermoplastic support sheet (T) to produce a sheet (F) bearing a coating(B), and drying and/or partially crosslinking the applied coatingcomposition (K) to give a coating (KT) that is not crosslinked tocompletion, II. inserting the resulting sheet (F) into an opened mold,III. closing the mold, contacting a side (T2) of the thermoplasticsupport sheet (T) not facing the surface (T1) with a liquid or softenedpolymeric material (KM), and causing the polymeric material to solidify,IV. removing the molding from the mold, and V. crosslinking the coating(KT) to completion at any point in time in the course of the process togive a transparent coating (KE), wherein the crosslinkable coatingcomposition (K) comprises a free-radically crosslinkable component (KK)comprising 70% to 100% by weight, based on the solids content ofcomponent (KK) of one or more oligo- and/or one or more poly-urethane(meth)acrylates, wherein the component KK has a number-average molecularweight of from 1000 to 10 000 g/mol, on average more than oneethylenically unsaturated double bond per molecule, a double bondcontent of from 1.0 to 5.0 mol of double bonds per 1000 g of reactivecomponent (KK), on average greater than one branching point permolecule, from 5%-50% by weight, based in each case on the weight ofcomponent (KK), of cycloaliphatic, heterocyclic and/or aromatic cyclicstructural units, and at least one aliphatic structural unit having 6 to18 carbon atoms in a chain, and one or more of carbamate, biuret,allophanate, urea, amide groups or mixtures thereof, wherein asolventborne or aqueous coating composition is used as pigmented coatingcomposition (P).
 2. The process of claim 1, wherein the free-radicallycrosslinkable component (KK) comprises an average carbamate and/orbiuret and/or allophanate and/or urea and/or amide groups content ofmore than 0 to 2.0 mol per 1000 g of reactive component (KK).
 3. Theprocess of claim 2, wherein the free-radically crosslinkable component(KK) comprises an average carbamate and/or biuret and/or allophanateand/or urea and/or amide groups content of from 0.1 to 1.1 mol per 1000g of reactive component (KK).
 4. The process of claim 3, wherein thefree-radically crosslinkable component (KK) comprises an averagecarbamate and/or biuret and/or allophanate and/or urea and/or amidegroups content of from 0.2 to 0.7 mol per 1000 g of reactive component(KK).
 5. The process of claim 1, wherein the free-radicallycrosslinkable component (KK) comprises more than 2 to 10.0 double bondsper molecule.
 6. The process of claim 5, wherein the free-radicallycrosslinkable component (KK) further comprises aliphatic structuralunits having 4 or 5 carbon atoms in the chain.
 7. The process of claim1, wherein the free-radically crosslinkable component (KK) comprises, ascyclic structural units, monocyclic structural units having 4 to 8 ringmembers and/or dicyclic and/or tricyclic and/or polycyclic structuralunits having 7 to 18 ring members and/or wherein the cyclic structuralunits are substituted.
 8. The process of claim 1, wherein thefree-radically crosslinkable component (KK) comprises as cyclicstructural units at least one of (i) cycloaliphatic structural units,(ii) heterocyclic structural units in which the number of heteroatomsper ring is 1 to 8 and/or in which the heteroatoms are selected from thegroup consisting of nitrogen, oxygen, sulfur, and mixtures thereof,(iii) aromatic structural units, (iv) and mixtures thereof, the amountof aromatic structural units being not more than 10% by weight, based ineach case on the weight of component (KK).
 9. The process of claim 1,wherein the free-radically crosslinkable component (KK) comprises, assubstituted or unsubstituted cyclic structural units, at least one ofthe group consisting of tricyclodecane rings, cyclohexane rings,isocyanurate rings, triazine rings, and mixtures thereof.
 10. Theprocess of claim 1, wherein the branching points of the free-radicallycrosslinkable component (KK) are introduced via the use of at least oneof isocyanates having a functionality of more than 2, isocyanuraterings, and mixtures thereof, in the synthesis of component (KK).
 11. Theprocess of claim 1, wherein the free-radically crosslinkable component(KK) has been prepared using at least one of hexamethylene diisocyanate,isophorone diisocyanate, methylenebis(4-isocyanatocyclohexane), one ormore of the corresponding isocyanurates thereof, one or more of thecorresponding biurets thereof, one or more of the correspondingallophanates of these isocyanates, hydroxyethyl acrylate, 4-hydroxybutylacrylate, pentaerythrityl triacrylate, isopropylidenedicyclohexanol, andmixtures thereof.
 12. The process of claim 1, wherein the free-radicallycrosslinkable component (KK) contains less than 5%, by weight, based onthe weight of component (KK), of detectable free isocyanate groups. 13.The process of claim 1, wherein the pigmented coating composition (P)comprises (I) one or more solvents and/or water, (II) one or morebinders selected from polyurethane resins, acrylate resins, mixturesthereof, and (III) optionally at least one crosslinking agent, (IV) atleast one pigment, and (V) optionally one or more customary auxiliariesand additives.
 14. The process of claim 1, wherein the pigmented coatingcomposition (P) is applied either in only one layer by means of anondirected application method or in two or more layers, in which casethe last of these layers is applied by means of a nondirectedapplication method.
 15. The process of claim 14, wherein the sheet (F)has been or is thermoformed.
 16. The process of claim 1, wherein thefree-radically crosslinkable component (KK) contains less than 1%, byweight, based on the weight of component (KK), of detectable freeisocyanate groups.
 17. The sheet (F) produced by the process of claim 1.18. A molding comprising a polymeric material (KM) provided with amultilayer sheet, wherein the polymeric material (KM) has been providedwith a sheet (F) as claimed in claim
 17. 19. The molding of claim 18that is at least one of an interior bodywork component, an exteriorbodywork component, a shipbuilding component, an aircraft constructioncomponent, a household appliance component, or an electrical appliancecomponent.